CN1649418A - camera device - Google Patents

Abstract

The invention provides an image pickup apparatus which can improve white balance adjustment precision and obtain a proper white balance image. An imaging device of the present invention includes: an image signal processing circuit (4) that performs white balance adjustment on the image signal output from the imaging element (2a) in accordance with the white balance gain; a ROM (6) for storing at least a white balance correction coefficient correspondence table and a white balance correction coefficient correspondence table; and a microcomputer (5) that performs the following control: a white balance correction coefficient and a white balance correction coefficient corresponding to the aperture value are calculated from the correspondence table, and a value obtained by multiplying the white balance correction coefficient and the white balance correction coefficient by the white balance gain is set as a digital gain, and white balance adjustment is performed based on the digital gain.

Description

camera device

technical field

The present invention relates to a technique for adjusting the white balance of an imaging device having an imaging element.

Background technique

[Patent Document 1] JP-A-2000-244930

Conventionally, for example, as shown in FIG. 11 , in order to increase the condensing efficiency of each pixel, each pixel of many imaging elements has a microlens 100 and a color filter 101, etc., but the refractive index of the microlens 100 depends on the intensity of incident light. wavelength (wavelength dependence).

In particular, as shown in FIG. 11 , when light is incident from an oblique direction on the microlens 100 , the above-mentioned wavelength dependence is significant, and light of a wavelength that is not collected on the light receiving unit 102 occurs (oblique incidence characteristic). Therefore, when the incident angle of light incident on the imaging element changes due to the diaphragm of the photographing lens or the like, poor white balance adjustment may occur.

Here, Patent Document 1 discloses a technique for reading a white balance fine adjustment coefficient stored in advance based on the focal length and aperture value of an interchangeable lens, and correcting the white balance adjustment value based on the coefficient.

However, in the technique described in Patent Document 1, no consideration is given to variations during manufacturing of the imaging element, optical characteristics of microlenses arranged for each pixel, and the like. For example, in the case where imaging elements with different optical characteristics can be used, no consideration is given to how the optical characteristics of the taking lens affect the accuracy of white balance adjustment.

Contents of the invention

The purpose of the present invention is to improve the accuracy of white balance adjustment, and to obtain an appropriate white balance image no matter what combination is used in an imaging device with interchangeable imaging lenses and imaging elements.

In order to achieve the above object, according to the first aspect of the present invention, an imaging device is provided, which is characterized in that the imaging device has: an imaging unit having an imaging element, and the imaging element captures an object image passing through the imaging lens, and outputs Image signal, the photographic lens has an aperture to control the amount of light; the storage unit stores the white balance correction coefficient, and the white balance correction coefficient is used to further correct the white balance correction coefficient according to the optical characteristics of the above-mentioned camera unit, and the white balance correction coefficient is used White balance correction is performed on the image signal output from the imaging unit in accordance with the characteristics of incidence to the imaging element based on the optical characteristics including the aperture setting of the imaging lens and an adjustment control unit that adjusts the white balance of the image signal output from the imaging unit based on the white balance correction coefficient corrected using the white balance correction coefficient.

According to a second aspect of the present invention, there is provided an imaging device in the first aspect, wherein the imaging lens is detachably attached to the imaging device, and the white balance correction coefficient is stored in the imaging lens.

According to a third aspect of the present invention, there is provided an imaging device, which is characterized in that the imaging device includes: an imaging unit that captures an image of an object passing through an optical system and outputs an image signal; The image signal output by the camera unit is adjusted for white balance; and the control unit performs the control of: reading a white balance correction coefficient and a white balance correction coefficient for performing correction corresponding to the characteristics of the aperture of the above-mentioned optical system , the white balance correction coefficient further corrects the white balance correction coefficient, and is used for correction corresponding to the optical characteristics of the above-mentioned camera unit; a digital gain is calculated according to the white balance correction coefficient and the white balance correction coefficient, and the digital gain is used for amplifying the signal of each color contained in the image signal output from the above-mentioned imaging unit; and performing white balance adjustment of the above-mentioned image signal processing unit according to the digital gain.

According to a fourth aspect of the present invention, there is provided an imaging device in the third aspect, wherein at least the imaging unit is detachable from the imaging device, and the white balance correction coefficient is stored in the imaging unit. .

According to a fifth aspect of the present invention, there is provided an image pickup device in the above-mentioned third aspect, wherein the white balance correction coefficient has at least a light-receiving position corresponding to a light-receiving position outside the optical axis of the light-receiving part captured by the imaging unit. A correction coefficient corresponding to the characteristic, the above-mentioned white balance correction coefficient has a coefficient for correcting the value of the white balance correction coefficient.

According to a sixth aspect of the present invention, there is provided an image pickup device capable of performing pre-shooting before actual shooting. In the pre-shooting, a gain for white balance adjustment is calculated by pre-shooting an object serving as a white reference, wherein the The imaging device has: an imaging unit, which captures the image of the subject passing through the optical system, and outputs an image signal; an image signal processing unit, which adjusts the white balance of the image signal output from the above-mentioned imaging unit; , perform the following control: read out the first white balance correction coefficient, the first white balance correction coefficient is used for correction corresponding to the characteristics of the aperture of the above-mentioned optical system, and corresponds to the aperture value at the time of photographing in advance; and read out the first white balance correction coefficient 2 white balance correction coefficients, white balance correction coefficients, the second white balance correction coefficients are used to perform corrections corresponding to the characteristics of the aperture of the above-mentioned optical system, and correspond to the aperture values at the time of actual photography, and the white balance correction coefficients correspond to the second white balance correction coefficients 1 and the second white balance correction coefficient are further corrected for correction corresponding to the optical characteristics of the above-mentioned camera unit; the digital gain is calculated by using the first and second white balance correction coefficient and the white balance correction coefficient, and the digital gain is used amplifying the signal of each color contained in the image signal output from the above-mentioned camera unit; and performing white balance adjustment of the above-mentioned image signal processing unit according to the digital gain.

According to a seventh aspect of the present invention, there is provided an imaging device, which is characterized in that the imaging device includes: an imaging unit that captures an image of a subject passing through an optical system and outputs an image signal; The image signal output by the camera unit is adjusted for white balance; the storage unit stores at least a first table and a second table, and the first table correlates the aperture value with a white balance correction coefficient, and the white balance correction coefficient is used for performing the above optical The correction corresponding to the characteristics of the aperture of the system, the second table associates the white balance correction coefficient with the white balance correction coefficient, and the white balance correction coefficient further corrects the white balance correction coefficient for the above-mentioned camera unit. The correction corresponding to the optical characteristics; and the control unit, which performs the following control: calculate the white balance correction coefficient and the white balance correction coefficient corresponding to the aperture value according to the above-mentioned first table and the second table; The value obtained by multiplying the coefficient and the above-mentioned white balance gain is used as a digital gain, which is used to amplify the signal of each color included in the image signal output from the above-mentioned camera unit; the above-mentioned image signal processing is performed according to this digital gain Unit's white balance adjustment.

According to an eighth aspect of the present invention, there is provided an imaging device, characterized in that the imaging device includes: an imaging unit that captures an image of an object passing through an optical system and outputs an image signal; The image signal output by the camera unit is adjusted for white balance; the storage unit stores at least a first table and a second table, and the first table correlates the aperture value with a white balance correction coefficient, and the white balance correction coefficient is used for performing the above optical The correction corresponding to the characteristics of the aperture of the system, the second table associates the white balance correction coefficient with the white balance correction coefficient, and the white balance correction coefficient further corrects the white balance correction coefficient for the above-mentioned camera unit. Correction corresponding to the optical characteristics; and the control unit, when actually shooting, performs the following control: calculate the first white balance correction coefficient corresponding to the aperture value at the time of prior shooting according to the above-mentioned first table, and according to the above-mentioned first table and the second The table reads the second white balance correction coefficient and white balance correction coefficient corresponding to the aperture value at the time of actual shooting; the value obtained by dividing the second white balance correction coefficient by the first white balance correction coefficient, the above white balance correction coefficient and the above The value obtained by multiplying the white balance gain is used as a digital gain, and the digital gain is used to amplify the signal of each color contained in the image signal output from the above-mentioned camera unit; and perform the above-mentioned image signal processing unit according to the digital gain. White balance adjustment.

According to a ninth aspect of the present invention, there is provided an imaging device, characterized in that the imaging device includes: an imaging unit that captures an image of a subject passing through an optical system and outputs an image signal; a gain for adjusting the white balance of the image signal output from the camera unit; a storage unit for storing at least a first table and a second table, the first table correlating the aperture value with the white balance correction coefficient, the white balance correction coefficient is used In performing correction corresponding to the characteristics of the aperture of the optical system, the second table associates the white balance correction coefficient with the white balance correction coefficient, and the white balance correction coefficient further corrects the white balance correction coefficient for performing The correction corresponding to the optical characteristics of the above-mentioned imaging unit; the switching unit for switching the shooting mode; Corresponding white balance correction coefficient, white balance correction coefficient; The value obtained by multiplying the white balance correction coefficient, white balance correction coefficient and the above-mentioned white balance gain is used as a digital gain, and the digital gain is used to convert the image output from the above-mentioned camera unit The signal of each color contained in the signal is amplified; according to the digital gain, the white balance adjustment of the above-mentioned image signal processing unit is carried out; in the second shooting mode, the following control is performed: according to the above-mentioned first table readout and the aperture in advance shooting value corresponding to the first white balance correction coefficient, and read out the second white balance correction coefficient and the white balance correction coefficient corresponding to the actual aperture value at the time of shooting according to the above-mentioned first table and the second table; the second white balance correction coefficient A value obtained by dividing by the first white balance correction coefficient and a value obtained by multiplying the above-mentioned white balance correction coefficient by the above-mentioned white balance gain is used as a digital gain. Amplify the signal of one color; adjust the white balance of the above-mentioned image signal processing unit according to the digital gain.

According to a tenth aspect of the present invention, there is provided an imaging device in the seventh to ninth aspects, wherein the second table is predetermined based on the optical characteristics of the imaging element.

According to an eleventh aspect of the present invention, there is provided an imaging device that obtains image data by capturing an object image obtained by an interchangeable imaging lens using an imaging unit, wherein the imaging device has: a correction coefficient a storage unit for storing correction coefficients for correcting corresponding to the optical characteristics of the photographing lens; a correction coefficient storage unit for storing correction coefficients for correcting the correction corresponding to the optical characteristics of the imaging unit a coefficient; and a white balance adjustment unit that adjusts the white balance of the image data obtained by the imaging according to the correction coefficient and the correction coefficient corresponding to the photographic lens used.

According to a twelfth aspect of the present invention, there is provided an imaging device, wherein in the above eleventh aspect, the correction coefficient storage unit is provided in the imaging lens, and the imaging device further includes: a communication unit for receiving data received from the imaging lens. The correction factor sent by the lens.

According to a thirteenth aspect of the present invention, there is provided an imaging device in the above-mentioned eleventh aspect, wherein the correction coefficient storage unit is provided in a device in which the imaging unit is disposed.

According to a fourteenth aspect of the present invention, there is provided an imaging device, characterized in that the imaging device includes: an imaging unit that uses an imaging element to capture an image of a subject passing through an interchangeable imaging lens, and outputs an image signal; A unit for adjusting the white balance of the image signal output from the imaging unit; a storage unit for storing a white balance correction coefficient corresponding to the optical characteristics of the mounted interchangeable lens and a white balance correction coefficient corresponding to the optical characteristics of the imaging unit ; and a control unit for performing the following control: adjusting the white balance according to the above-mentioned white balance correction coefficient and the white balance correction coefficient.

According to a fifteenth aspect of the present invention, there is provided an imaging device in the fourteenth aspect, wherein a white balance correction coefficient corresponding to the optical characteristics of the interchangeable lens and a white balance correction coefficient corresponding to the optical characteristics of the imaging unit are provided. The correction coefficient is a coefficient for an imaging element having a reference optical characteristic.

According to the present invention, the accuracy of white balance adjustment can be improved, and an appropriate white balance image can be obtained regardless of any combination in an imaging device in which a photographic lens and an imaging element are replaceable.

Description of drawings

FIG. 1 is a configuration diagram of an imaging device according to a first embodiment of the present invention.

FIG. 2 is a graph showing a spectral sensitivity distribution of an imaging element.

FIG. 3 is a graph showing the incident-angle dependence characteristic of the light-receiving sensitivity of the imaging element.

FIG. 4 is a graph showing the F-value dependence characteristic of the output of the imaging element.

FIG. 5 is a diagram showing a WB (that is, white balance, hereinafter referred to as WB) correction coefficient correspondence table.

FIG. 6 is a diagram showing a WB correction coefficient correspondence table.

FIG. 7 is a flowchart showing the operation of the imaging device according to the first embodiment of the present invention at the time of pre-shooting.

8 is a flowchart showing the operation of the imaging device according to the first embodiment of the present invention at the time of actual imaging.

9 is a diagram showing a WB correction coefficient correspondence table employed by the imaging device according to the second embodiment of the present invention.

10 is a diagram showing a WB correction coefficient correspondence table employed by the imaging device according to the third embodiment of the present invention.

FIG. 11 is an explanatory diagram related to wavelength dependence and oblique incidence characteristics of an imaging element according to the prior art.

[Symbol Description]

1: lens module; 1a: optical system; 1b: microcomputer; 1c: ROM; 2: camera module; 2a: camera element; 2b: I/F circuit; 2c: ROM; 3: RAM; 4: image signal processing circuit ;4a: digital gain circuit; 4b: synchronization circuit; 4c: color conversion circuit; 4d: gamma conversion circuit; 5: microcomputer; 6: ROM; 7: EEPROM; 8: mode setting switch; 9: storage medium.

Detailed ways

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(first embodiment)

First, a configuration of an imaging device according to a first embodiment of the present invention will be described with reference to FIG. 1 .

Here, as an example of the imaging device, a camera system in which an interchangeable imaging lens (hereinafter referred to as an interchangeable lens) is combined with a camera body will be described as an example.

As shown in FIG. 1, the camera system as the imaging device according to the first embodiment of the present invention includes: a lens module 1, a camera module 2, a RAM 3, an image signal processing circuit 4, a microcomputer (hereinafter referred to as a microcomputer) 5, and a ROM 6. , EEPROM7, mode setting switch 8, storage medium 9, etc. The lens module 1 is disposed on the side of the interchangeable lens, and other components are disposed on the side of the camera body to which the interchangeable lens can be mounted. The lens module 1 and the camera module 2 can be freely attached or detached through the connector, and are electrically connected through the communication part 1d.

In the lens module 1 on the interchangeable lens side, an optical system 1a including a photographic lens, a zoom lens, and a diaphragm, etc.; a microcomputer 1b that controls the entire lens module; a ROM 1c that stores various data, etc.; a communication unit 1d, etc. are provided. . At least a first table is stored in this ROM 1c, and details will be described later.

In addition, an imaging element 2a such as a CCD, an interface (hereinafter referred to as I/F) circuit 2b, and a ROM 2c for temporarily storing various data are provided in the imaging module 2 on the camera body side. The RAM 3 interposed between the camera module 2 and the image signal processing circuit 4 is used to store image signals sent from the I/F circuit 2b. The camera module 2 is detachably mounted on the camera body via a connector, and is electrically connected via the communication unit 10 .

More specifically, the image signal processing circuit 4 includes a digital gain circuit 4a, a synchronization circuit 4b, a color conversion circuit 4c, and a gamma conversion circuit 4d.

The digital gain circuit 4a is used to convert the R (red) signal, Gr (green) signal, Gb ( Green) signal and B (blue) signal are amplified, and as level-adjusted signals, R' signal, Gr' signal, Gb' signal, and B' signal are output.

That is, the digital gain is used to amplify the signal for each color contained in the image signal output from the imaging element 2a.

Furthermore, the synchronization circuit 4b includes a sample-and-hold circuit not shown, etc., and is used to perform synchronization processing of the R' signal, the Gr' signal, the Gb' signal, and the B' signal, and output the R signal, the G signal, and the B signal. . The color conversion circuit 4c is used for performing color conversion on the R signal, the G signal, and the B signal, and outputting the R' signal, the G' signal, and the B' signal. Furthermore, the gamma conversion circuit 4d performs γ conversion on the R' signal, the G' signal, and the B' signal, and stores the result in the storage medium 9.

In addition to the above, ROM 6 is used to store at least a second table described in detail later. EEPROM7 is used to store various data. The mode setting switch 8 is used to switch various modes.

Furthermore, the imaging unit described in the claims corresponds to the imaging element 2a or the imaging module 2 including the imaging element 2a, the image signal processing unit corresponds to the image signal processing circuit 4, etc., and the storage unit corresponds to the ROM 1c in the lens module 1. Or the ROM6 etc. on the side of the camera body, the control unit corresponds to the microcomputer 5 etc.

In addition, the correction coefficient storage unit described in the claims corresponds to the ROM 1c of the lens module 1, etc., the correction coefficient storage unit corresponds to the ROM 6 and the like, and the white balance adjustment unit corresponds to the image signal processing circuit 4 and the like.

Furthermore, the communication unit corresponds to the communication units 1d, 10, and the like. However, it is not limited to the above relationship.

In this configuration, the subject image incident through the imaging lens, zoom lens, and diaphragm of the optical system 1a of the lens module 1 is captured by the imaging element 2a of the imaging module 2, and the image signal is output to the stored in RAM3.

In the ROM 1c of the lens module 1 on the interchangeable lens side, at least a first table is stored which associates the aperture value with a white balance (hereinafter referred to as WB) correction coefficient for performing adjustment with the aperture of the optical system 1a. Correction corresponding to the characteristic.

Here, the WB correction coefficient is a coefficient for performing correction corresponding to the characteristics of the diaphragm of the optical system 1 a in the present embodiment.

On the other hand, in the ROM 6 on the side of the camera body, at least a second table is stored which correlates WB correction coefficients and WB correction coefficients which further correct the WB correction coefficients and are used for the image sensor 2a. Correction corresponding to optical characteristics.

Here, the WB correction coefficient is a coefficient for further correcting the WB correction coefficient and performing correction corresponding to the optical characteristics of the imaging element 2 a used.

This second table is determined in advance based on the optical characteristics of the imaging element 2a.

The storage address of each table is an example, and of course it is not limited thereto.

The microcomputer 5 calculates a digital gain based on the WB mode set by the mode setting switch 8 . Here, the case where there are two different modes, the first WB mode and the second WB mode, as the WB mode will be described below.

For example, the operation in the first WB mode is performed as follows. That is, the WB correction coefficient and the WB correction coefficient corresponding to the aperture value are calculated based on the first table and the second table.

And, the value obtained by multiplying the WB correction coefficient and the WB correction coefficient by the above-mentioned WB gain is used as a digital gain, and this digital gain is used to amplify the signal for each color included in the image signal output from the above-mentioned imaging element 2a. .

Digital gain=WB gain×WB correction coefficient×WB correction coefficient…(1)

Control is performed so that the WB adjustment of the image signal processing circuit 4 is performed based on this digital gain.

The image signal of RAM 3 is read out by the image signal processing circuit 4, and the white balance of the image signal is adjusted based on the digital gain calculated above.

On the other hand, the operation in the second WB mode is performed as follows. That is, the microcomputer 5 calculates the first WB correction coefficient corresponding to the aperture value at the time of prior shooting based on the above-mentioned first table.

Here, the prior photography refers to photography for obtaining predetermined data before the actual photography of the subject image, whereas the photography of the actually required subject image is referred to as real photography.

Then, the second WB correction coefficient and the WB correction coefficient corresponding to the aperture value at the time of actual shooting are read from the first table and the second table.

Furthermore, a value obtained by dividing the second WB correction coefficient by the first WB correction coefficient and a value obtained by multiplying the above-mentioned WB correction coefficient by the above-mentioned WB gain are used as a digital gain, and this digital gain is used to convert the image signal output from the above-mentioned imaging element 2a into The signal contained in each color is amplified.

Digital Gain=WB Gain×(WB Correction Coefficient (F value during actual shooting)/WB Correction Coefficient (F value during prior shooting))×WB Correction Coefficient (WB Correction Coefficient during real shooting)

…(2)

Control is performed so that the WB adjustment of the image signal processing circuit 4 is performed based on this digital gain.

The image signal of the RAM 3 is read out by the image signal processing circuit 4, and WB adjustment is performed on the image signal based on the digital gain calculated above.

Here, the spectral sensitivity distribution of the imaging element is shown in FIG. 2 for description.

The imaging element 2a has the spectral sensitivity characteristics shown in FIG. 2 . The characteristics of each light component of R, G, and B are shown in FIG. 2 , and the sensitivity of the human eye to color is strongest for the G light component, which appears brightest.

In addition, the imaging module 2 including the imaging element 2a can be replaced with another imaging module having an imaging element having a different optical characteristic. In this way, it is possible to use a camera module suitable for the purpose of photography, such as a camera module suitable for night photography and a camera module suitable for a wide dynamic range.

The incident angle dependence characteristic of the light-receiving sensitivity of the imaging element is shown in FIG. 3 and described.

As shown in FIG. 3 , the imaging element 2 a has an incident angle dependence, and a difference in relative sensitivity occurs depending on the incident angle of light. That is, as the incident angle of light increases, a difference occurs in the reduction of the relative sensitivity of the R, G, and B light components. In addition, in particular, the degree of decline increases when expressed as the relative sensitivity (R/G, B/G) of the G light component. Furthermore, the degree of the variation differs for each imaging element due to variations in the design of the microlens and the manufacturing of the imaging element 2a.

The F-value dependence characteristic of the output of the imaging element will be described in FIG. 4 .

As shown in FIG. 4, even if the microlenses provided for each pixel are produced under the same design, in the relationship between the reciprocal of the F value (1/F) and the relative sensitivity (R/G, B/G), as When the 1/F value increases (that is, the aperture is opened), the relative sensitivity of the R, G, and B light components decreases. Furthermore, the degree of decrease in the relative sensitivity greatly differs for each light component.

In view of the above features, in the imaging device according to one embodiment of the present invention, the digital gain is calculated using the WB correction coefficient correspondence table as the first table and the WB correction coefficient correspondence table as the second table, and the digital gain is calculated based on the digital gain The signal of each color is amplified. Details are given below.

First, a WB correction coefficient correspondence table is shown in FIG. 5 for description.

As shown in FIG. 5 , the WB correction coefficient correspondence table associates the aperture value with the WB correction coefficients of the R and B signals. In this WB correction coefficient correspondence table, one selected imaging element is determined at the position of the reference imaging element, and correction coefficients for the gain of the R signal and the B signal are determined based on the incident angle dependence of the reference imaging element, etc. . As described above, the incident angle dependence of the imaging element is such that as the incident angle increases, the relative sensitivity of the R signal and the B signal significantly decreases, and the WB correction coefficient corrects the decrease. In addition, this WB correction coefficient correspondence table is stored, for example, in ROM1c in the lens module 1 of FIG. 1, etc. FIG.

Next, a WB correction coefficient correspondence table is shown in FIG. 6 for description.

As shown in FIG. 6 , the WB correction coefficient correspondence table associates the WB correction coefficients read from FIG. 5 with the WB correction coefficients of the R and B signals.

For example, if the WB correction coefficient is 1.03, the WB correction coefficient_R corresponding to the optical characteristics of the imaging element 2a is 1.01 and the WB correction coefficient_B is 0.99 according to the WB correction coefficient correspondence table.

And, this WB correction coefficient correspondence table is stored in the ROM 2 c of the camera module 2 .

In the imaging device according to the present embodiment, the microcomputer 5 calculates the digital gain by referring to the correspondence tables in FIGS. 5 and 6 .

More specifically, the microcomputer 5 refers to the correspondence table in FIG. 5 and reads out the WB correction coefficient_R and the WB correction coefficient_B corresponding to the aperture value of the optical system 1 a from the ROM 1 c.

Then, referring to the correspondence table in FIG. 6 , the WB correction coefficient _R corresponding to the WB correction coefficient _R and the WB correction coefficient _B corresponding to the WB correction coefficient _B are read out from the ROM 6 . Then, a digital gain is calculated from these coefficients. For example, the microcomputer 5 calculates the digital gain according to Equation (1) in the first WB mode, and calculates the digital gain according to Equation (2) in the second WB mode.

Hereinafter, the operation of the imaging device according to one embodiment of the present invention at the time of pre-imaging will be described in detail with reference to the flowchart of FIG. 7 . Here, refer to FIGS. 5 and 6 as appropriate.

When a release switch (not shown) is pressed to enter the pre-shooting operation, first, the microcomputer 5 performs predetermined photometry calculations, exposure control, and imaging control (steps S1 to S3). Then, the imaging data (image signal) from the imaging element 2a is stored in the RAM 3 (step S4).

Then, the microcomputer 5 detects the WB gain from the image signal (step S5), and stores the WB gain in the EEPROM 7 (step S6).

And, the F value at the time of the previous shooting is stored in the EEPROM 7 (step S7), and the operation at the time of the previous shooting is ended.

Through the processing of the above example, the WB gain and the F value at the time of pre-shooting used in the later processing are stored in EEPROM 7 in association with each other.

Next, with reference to the flowchart of FIG. 8 , the operation of the imaging device according to one embodiment of the present invention at the time of actual imaging will be described in detail. Here, also refer to FIGS. 5 and 6 as appropriate.

When entering the actual photographing operation, first, the microcomputer 5 performs predetermined light metering calculations, exposure control, and imaging control (steps S11 to S13). The imaging element 2a stores the imaging data (image signal) in the RAM 3 (step S14). Then, referring to the WB correction coefficient correspondence table in FIG. 5 , the WB correction coefficient_R and WB correction coefficient_B corresponding to the F value at the time of actual shooting are read (from the ROM 1c) (step S15).

Then, referring to the WB correction coefficient correspondence table in FIG. 6, the WB correction coefficient_R and WB correction coefficient_B corresponding to the above-mentioned WB correction coefficient_R and WB correction coefficient_B are read (from ROM 6) (step S16).

Then, the microcomputer 5 judges whether the WB mode is set to automatic WB (hereinafter referred to as AWB), manual WB (hereinafter referred to as MWB), or single-press WB (hereinafter referred to as OTWB) through the mode setting switch 8 (step S17).

Here, the AWB mode is a mode in which white balance adjustment suitable for a scene is automatically performed based on imaging data.

Also, the MWB mode is a mode in which a photographer manually designates white balance adjustment suitable for a scene in advance.

Furthermore, the OTWB mode is a mode for performing white balance adjustment based on a gain for white balance adjustment obtained by photographing a subject as a white reference in advance.

First, in step S17, when it is determined that the AWB mode is set, the microcomputer 5 analyzes the above-mentioned imaging data, and performs a determination on the WB gain (step S18).

Then, by combining the WB correction coefficient_R and WB correction coefficient_B read in step S15, the WB correction coefficient_R and WB correction coefficient_B read in step S16, and the WB correction coefficient obtained in step S18 The gain is substituted into the above calculation formula (1), and the digital gain of the R signal and the B signal is calculated (step S19).

Then, the process proceeds to step S25 and subsequent processes.

On the other hand, when the microcomputer 5 determines in step S17 that the MWB mode is set, it reads out the WB gain previously designated by the photographer from the ROM 6 (step S20).

Then, the judgment of step S21 goes to the MWB side, and the WB correction coefficient_R and WB correction coefficient_B read in step S15, the WB correction coefficient_R and WB correction coefficient_B read in step S16, And the WB gain obtained in step S20 at the time of prior imaging is respectively substituted into the above calculation formula (1), and the digital gains of the R signal and the B signal are calculated (step S19 ).

Then, the process proceeds to step S25 and subsequent processes. Here, the gain for white balance adjustment designated in the MWB mode is stored in the ROM 6 in advance.

Furthermore, when the microcomputer 5 determines in step S17 that the OTWB mode is set, it reads out (from the EEPROM 7 ) the WB gain obtained at the time of prior imaging (step S20 ). Then, the judgment in step S21 goes to the OTWB side, and the F value at the time of pre-shooting is read (step S22), and the WB correction coefficient at the time of pre-shooting is read from EEPROM 7 (step S23). Then, the WB correction coefficient_R and WB correction coefficient _B at the time of real photography read in step S15, the WB gain at the time of pre-photographing read at step S20, and the pre-scanning gain at the time of step S22 and S23 are combined. The F value, WB correction coefficient_R and WB correction coefficient_B at the time of photography are respectively substituted into the above calculation formula (2), and the digital gains of the R signal and the B signal are calculated (step S24 ). After that, it proceeds to step S25 and subsequent processes.

In this way, the digital gain circuit 4a amplifies the R signal, the Gr signal, the Gb signal, and the B signal, which are image signals temporarily stored in the RAM 3, by using the digital gain calculated by the microcomputer 5 to adjust the level and output the R' signal. , Gr' signal, Gb' signal, and B' signal (step S25).

Furthermore, the synchronization circuit 4b performs synchronization processing of the R' signal, the Gr' signal, the Gb' signal, and the B' signal, and outputs the R signal, the G signal, and the B signal.

Then, the color conversion circuit 4c performs color conversion on the R signal, the G signal, and the B signal, and outputs the R' signal, the G' signal, and the B' signal. Then, the gamma conversion circuit 4d performs γ conversion on the R' signal, the G' signal, and the B' signal (step S26).

The result thus obtained is stored in the storage medium 9 (step S27).

(second embodiment)

In the imaging device according to the second embodiment of the present invention, the imaging module equipped with the CCD having the WB correction coefficient correspondence table and its characteristics shown in FIG. The characteristics of the case of the CCD camera module will be described. As the CCD of this imaging module, a CCD having a narrower interval between adjacent pixels than the imaging element 2a (hereinafter referred to as a narrow-pitch module) is used.

Here, as shown in FIG. 1 , the camera module and the lens module are electrically connected through the communication unit 1d. In addition, the camera module is electrically connected to the microcomputer and ROM 3 of the camera device through the communication unit 10 . An example of the communication unit 1d and the communication unit 10 is that the camera module can be detached by being configured as a connector.

In the imaging device according to the second embodiment of the present invention, the digital gain is calculated using the WB correction coefficient correspondence table in FIG. 5 as the first table and the WB correction coefficient correspondence table in FIG. 9 as the second table. This digital gain amplifies the signal for each color. Details are given below.

5 is explained in the previous embodiment, so it is omitted here, and the WB correction coefficient correspondence table in FIG. 9 will be described.

As shown in FIG. 9 , the WB correction coefficient correspondence table associates the WB correction coefficients read from FIG. 5 with the WB correction coefficients of the R and B signals.

Here, the WB correction coefficients in FIG. 9 are coefficients for further correcting more and less corrections relative to the optical characteristics of the reference imaging element. If the WB correction coefficient is corrected using the WB correction coefficient of the narrow-pitch module, the same correction as the appropriate WB correction performed in the first embodiment, for example, can be performed. Comparing Fig. 9 with Fig. 6, when viewing narrowly, the WB correction coefficient in Fig. 9 corresponding to the narrow-pitch module is more strongly affected by the incident angle, so the correction coefficient is also a coefficient with a large correction amount.

In addition, depending on the optical characteristics of the imaging element of the mounted imaging module, the correspondence relationship between the correction coefficient and each aperture and the precision resolution may be different so as to achieve optimum correction. For example, it is also possible to adopt a resolution that makes the corresponding relationship between the correction coefficient and each aperture value coincide with the correction amount, or have corrections for the zoom position not only for the telephoto (TELE) and wide-angle (WIDE) positions, but also for different focal lengths. coefficient.

This WB correction coefficient correspondence table is stored in the ROM 2 c of the camera module 2 as in the first embodiment.

(third embodiment)

In the imaging device according to the third embodiment of the present invention, a lens module (hereinafter referred to as a zoom lens module) equipped with a zoom lens having the WB correction coefficient correspondence table shown in FIG. The case of the WB correction coefficient correspondence table will be described.

Here, as shown in FIG. 1 , the camera module and the zoom lens module are electrically connected through the communication unit 1d. This communication part 1d is detachable by being comprised as a connector like 2nd Embodiment.

In the imaging device according to the third embodiment of the present invention, the digital gain is calculated using the WB correction coefficient correspondence table in FIG. 10 as the first table and the WB correction coefficient correspondence table in FIG. 6 as the second table. Digital gain amplifies the signal for each color. Details are given below.

The WB correction coefficient correspondence table in FIG. 10 will be described.

In the zoom lens, it happens that the influence of the aperture of the light beam incident on the imaging element differs depending on the focal length. Therefore, as shown in FIG. 5 , the WB correction coefficient correspondence table is used to correlate the aperture value with the WB correction coefficients of the R and B signals according to the focal lengths of the wide-angle side (WIDE) and the telephoto side (TELE). In addition, this WB correction coefficient correspondence table is stored, for example, in the ROM1c in the zoom lens module.

Here, the WB correction coefficients in FIG. 10 are coefficients indicating how much or how little is corrected with respect to the optical characteristics of the reference imaging lens. By performing correction using the WB correction coefficient of the zoom lens module and the WB correction coefficient of the camera module, correction similar to the appropriate WB correction performed in the first embodiment, for example, can be performed. As can be seen from FIG. 10 , the correction value of the WB correction coefficient is large even when the focal length is short (that is, on the wide-angle side) at the same aperture.

In addition, depending on the optical characteristics of the imaging lens of the mounted lens module, the correspondence relationship between the correction coefficient and each aperture and the precision resolution may be different so as to achieve optimum correction.

As described above, even when the combination of the lens module and the camera module is changed, appropriate WB correction can be performed in any of the above-mentioned embodiments.

)现象，可获得合适的曝光图像。As described above, according to the embodiment of the present invention, the WB adjustment accuracy can be improved, and the so-called color whitening (色かぶ) can be suppressed.

) phenomenon, a suitable exposure image can be obtained.

In addition, when calculating the digital gain for WB adjustment, appropriate processing corresponding to various imaging modes can be performed. In addition, it is possible to perform WB adjustment that fully takes into account variations in the manufacturing of the imaging element, optical characteristics of the microlens, and the like.

As mentioned above, although one embodiment of this invention was described, this invention is not limited to this, Various improvement and change are possible in the range which does not deviate from the summary of this invention.

Claims (15)

1. camera head, its imaging apparatus or photographic lens are replaceable, it is characterized in that, and this camera head has:

Image unit has imaging apparatus, and this imaging apparatus is taken the subject picture by photographic lens, and output image signal, and this photographic lens has the aperture of control light quantity;

Memory cell, storage white-balance correction coefficient, this white-balance correction coefficient is used for the optical characteristics according to above-mentioned image unit, the white balance augmenting factor is done further to revise, this white balance augmenting factor is used for corresponding to the characteristic of above-mentioned imaging apparatus incident, to carrying out the white balance revisal from the picture signal of above-mentioned image unit output, wherein, this characteristic to above-mentioned imaging apparatus incident is based on the aperture settings that comprises above-mentioned photographic lens in interior optical characteristics; And

Adjust control unit, according to using the revised white balance augmenting factor of above-mentioned white-balance correction coefficient, to carrying out the white balance adjustment from the picture signal of above-mentioned image unit output.

2. camera head according to claim 1 is characterized in that, above-mentioned photographic lens is removable to be loaded on the above-mentioned camera head, and above-mentioned white balance augmenting factor is stored in the above-mentioned photographic lens.

3. camera head, its imaging apparatus or photographic lens are replaceable, it is characterized in that, and this camera head has:

Image unit is taken the subject picture that has passed through optical system, and output image signal;

Image signal processing unit is to carrying out the white balance adjustment from the picture signal of above-mentioned image unit output; And

Control unit, carry out following control: read white balance augmenting factor and white-balance correction coefficient, this white balance augmenting factor is used to carry out the corresponding revisal of characteristic with the aperture of above-mentioned optical system, this white-balance correction coefficient is done further to revise to this white balance augmenting factor, is used to carry out the revisal corresponding with the optical characteristics of above-mentioned image unit; Calculate digital gain according to this white balance augmenting factor and white-balance correction coefficient, the signal that this digital gain is used for every kind of color that will be comprised in the picture signal of above-mentioned image unit output amplifies; Carry out the white balance adjustment of above-mentioned image signal processing unit according to this digital gain.

4. camera head according to claim 3 is characterized in that, above-mentioned image unit is removable to be loaded on the above-mentioned camera head, and above-mentioned white-balance correction coefficient is stored in the above-mentioned image unit.

5. camera head according to claim 3, it is characterized in that, above-mentioned white balance augmenting factor have at least with the outer light receiving position of the optical axis of the captured light accepting part of above-mentioned image unit be subjected to the corresponding augmenting factor of light characteristic, above-mentioned white-balance correction coefficient has the coefficient that the value of this white balance augmenting factor is revised.

6. camera head, its imaging apparatus or photographic lens are replaceable, before real photography, can photograph in advance, photography is in advance calculated white balance adjustment gain by taking the subject that becomes white reference in advance, it is characterized in that this camera head has:

Image unit is taken the subject picture that has passed through optical system, and output image signal;

Image signal processing unit is to carrying out the white balance adjustment from the picture signal of above-mentioned image unit output; And

Control unit, carry out following control: when real photography, read the 1st corresponding white balance augmenting factor of f-number when photographing in advance, the 1st white balance augmenting factor is used to carry out the corresponding revisal of characteristic with the aperture of above-mentioned optical system; And, read the 2nd white balance augmenting factor, white-balance correction coefficient, the 2nd white balance augmenting factor is used to carry out the corresponding revisal of characteristic with the aperture of above-mentioned optical system, and it is corresponding with the f-number in real when photography, this white-balance correction coefficient is done further to revise to the 1st and the 2nd white balance augmenting factor, is used to carry out the revisal corresponding with the optical characteristics of above-mentioned image unit; Use the 1st and the 2nd white balance augmenting factor, white-balance correction coefficient to calculate digital gain, the signal that this digital gain is used for every kind of color that will be comprised in the picture signal of above-mentioned image unit output amplifies; And the white balance adjustment of carrying out above-mentioned image signal processing unit according to this digital gain.

7. camera head, its imaging apparatus or photographic lens are replaceable, it is characterized in that, and this camera head has:

Image unit is taken the subject picture that has passed through optical system, and output image signal;

Image signal processing unit is according to carrying out the white balance adjustment from the picture signal of above-mentioned image unit output;

Memory cell, at least store the 1st table and the 2nd table, the 1st table is associated f-number with the white balance augmenting factor, this white balance augmenting factor is used to carry out the corresponding revisal of characteristic with the aperture of above-mentioned optical system, the 2nd table is associated this white balance augmenting factor with the white-balance correction coefficient, this white-balance correction coefficient is done further to revise to this white balance augmenting factor, is used to carry out the revisal corresponding with the optical characteristics of above-mentioned image unit; And

Control unit carries out following control: according to above-mentioned the 1st table and the 2nd table, calculate the white balance augmenting factor corresponding with f-number, white-balance correction coefficient; This white balance augmenting factor, white-balance correction coefficient and above-mentioned white balance gains are multiplied each other the value that obtains as digital gain, and the signal that this digital gain is used for every kind of color that will be comprised in the picture signal of above-mentioned image unit output amplifies; Carry out the white balance adjustment of above-mentioned image signal processing unit according to this digital gain.

8. camera head, its imaging apparatus or photographic lens are replaceable, it is characterized in that, and this camera head has:

Image unit is taken the subject picture that has passed through optical system, and output image signal;

Image signal processing unit is according to carrying out the white balance adjustment from the picture signal of above-mentioned image unit output;

Memory cell, at least store the 1st table and the 2nd table, the 1st table makes f-number be associated with the white balance augmenting factor, this white balance augmenting factor is used to carry out the corresponding revisal of characteristic with the aperture of above-mentioned optical system, the 2nd table makes this white balance augmenting factor be associated with the white-balance correction coefficient, this white-balance correction coefficient is done further to revise to this white balance augmenting factor, is used to carry out the revisal corresponding with the optical characteristics of above-mentioned image unit; And

Control unit, when real photography, carry out following control: the 1st corresponding white balance augmenting factor of f-number when calculating with photography in advance according to above-mentioned the 1st table, and read corresponding the 2nd white balance augmenting factor, the white-balance correction coefficient of f-number when really photographing according to above-mentioned the 1st table and the 2nd table; Value, above-mentioned white-balance correction coefficient and the above-mentioned white balance gains that the 2nd white balance augmenting factor is obtained divided by the 1st white balance augmenting factor multiplies each other the value that obtains as digital gain, and the signal that this digital gain is used for every kind of color that will be comprised in the picture signal of above-mentioned image unit output amplifies; And the white balance adjustment of carrying out above-mentioned image signal processing unit according to this digital gain.

9. camera head, its imaging apparatus or photographic lens are replaceable, it is characterized in that, and this camera head has:

Image unit is taken the subject picture that has passed through optical system, and output image signal;

Image signal processing unit is according to white balance gains, to carrying out the white balance adjustment from the picture signal of above-mentioned image unit output;

Memory cell, at least store the 1st table and the 2nd table, the 1st table is associated f-number with the white balance augmenting factor, this white balance augmenting factor is used to carry out the corresponding revisal of characteristic with the aperture of above-mentioned optical system, the 2nd table is associated this white balance augmenting factor with the white-balance correction coefficient, this white-balance correction coefficient is done further to revise to this white balance augmenting factor, is used to carry out the revisal corresponding with the optical characteristics of above-mentioned image unit;

Switch unit is used to switch photograph mode; And

Control unit when the 1st photograph mode, carries out following control: according to above-mentioned the 1st table and the 2nd table, read the white balance augmenting factor corresponding with f-number, white-balance correction coefficient; This white balance augmenting factor, white-balance correction coefficient and above-mentioned white balance gains are multiplied each other the value that obtains as digital gain, and the signal that this digital gain is used for every kind of color that will be comprised in the picture signal of above-mentioned image unit output amplifies; Carry out the white balance adjustment of above-mentioned image signal processing unit according to this digital gain; When the 2nd photograph mode, carry out following control: the 1st corresponding white balance augmenting factor of f-number when reading with photography in advance according to above-mentioned the 1st table, and read corresponding the 2nd white balance augmenting factor, the white-balance correction coefficient of f-number when really photographing according to above-mentioned the 1st table and the 2nd table; Value, above-mentioned white-balance correction coefficient and the above-mentioned white balance gains that the 2nd white balance augmenting factor is obtained divided by the 1st white balance augmenting factor multiplies each other the value that obtains as digital gain, and the signal that this digital gain is used for every kind of color that will be comprised in the picture signal of above-mentioned image unit output amplifies; And the white balance adjustment of carrying out above-mentioned image signal processing unit according to this digital gain.

10. according to any described camera head in the claim 7 to 9, it is characterized in that above-mentioned the 2nd table is what the optical characteristics according to imaging apparatus was predetermined.

11. a camera head, its imaging apparatus or photographic lens are replaceable, and this camera head looks like to obtain view data by using image unit to take the subject that is obtained by removable photographic lens, it is characterized in that this camera head has:

The augmenting factor memory cell, the storage augmenting factor, this augmenting factor is used to carry out the revisal corresponding with the optical characteristics of above-mentioned photographic lens;

The correction factor memory cell, the storage correction factor, this correction factor is used for the corresponding above-mentioned augmenting factor of revising with the optical characteristics of above-mentioned image pickup part; And

The white balance adjustment unit according to above-mentioned augmenting factor and the correction factor corresponding with the photographic lens that is adopted, is adjusted the white balance of the view data that above-mentioned shooting obtained.

12. camera head according to claim 11 is characterized in that, above-mentioned augmenting factor memory cell is arranged in the above-mentioned photographic lens, and above-mentioned camera head also has: communication unit, it receives the augmenting factor that sends from above-mentioned photographic lens.

13. camera head according to claim 11 is characterized in that, above-mentioned correction factor memory cell is arranged in the device that disposes above-mentioned image unit.

14. a camera head, its imaging apparatus or photographic lens are replaceable, it is characterized in that, this camera head has:

Image unit uses imaging apparatus to take the subject picture that passes through removable photographic lens, and output image signal;

Image signal processing unit is to carrying out the white balance adjustment from the picture signal of above-mentioned image unit output;

Memory cell is stored the white balance augmenting factor corresponding with the optical characteristics of the above-mentioned replacing lens of being installed, the white balance augmenting factor corresponding with the optical characteristics of above-mentioned image unit; And

Control unit carries out following control: carry out the white balance adjustment according to above-mentioned white balance augmenting factor and white-balance correction coefficient.

15. camera head according to claim 14, it is characterized in that, the white balance augmenting factor corresponding with the optical characteristics of above-mentioned replacing lens, with the corresponding white-balance correction coefficient of the optical characteristics of above-mentioned image unit be coefficient with respect to imaging apparatus with the optical characteristics that becomes benchmark.

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